March 17, 2016

Hydroxychloroquine Blood Levels May Be Helpful in Patients with "Antimalarial-Resistant" Cutaneous Lupus Erythematosus

Jeffrey P. Callen, MD reviewing Chasset F et al. J Am Acad Dermatol 2016 Apr.

Increasing the hydroxychloroquine dose to achieve adequate levels produced clinical response.

Hydroxychloroquine is standard therapy for patients with cutaneous lupus erythematous (CLE), but up to a third of patients appear to be refractory to this agent. Blood levels of hydroxychloroquine are measurable; levels below 750 ng/mL are considered inadequate.

These authors measured blood levels in patients with antimalarial-resistant CLE. Among 74 refractory patients, 36 (49%) had blood levels below 750 ng/mL. Investigators raised the daily hydroxychloroquine dose in 34 of these patients to obtain adequate blood levels, and measured clinical disease using a validated score (CLASI) before and after the intervention. The patients included had a mixture of clinical disease, including discoid LE, subacute CLE, indeterminate disease, chilblains, and lupus panniculitis. Half of the patients were tobacco smokers.

When patients achieved adequate hydroxychloroquine blood levels, their clinical disease responded. Even among smokers, increased dosing produced response. In most instances, daily dosing was able to be reduced to levels compatible with long-term ocular safety.

COMMENT

Despite a small cohort of patients, some with rarer cutaneous manifestations, the findings have important aspects. First, simply measuring hydroxychloroquine levels can identify noncompliant patients and lead to better patient education. Second, increasing the hydroxychloroquine dose to achieve adequate levels produced clinical response and might avoid agents with more potential toxicity. Third, it seems that the daily dosage can eventually be decreased for safer use. The authors note the small number of patients, but it might also have been better to include only patients with DLE and SCLE.

EDITOR DISCLOSURES AT TIME OF PUBLICATION

Disclosures for Jeffrey P. Callen, MD at time of publicationConsultant / Advisory boardXOMA; Eli Lilly; CelgeneEquityVarious trust accountsEditorial boardsJAMA Dermatology; UpToDateLeadership positions in professional societiesAssociation of Professors of Dermatology (President-Elect)

CITATION(S):

Chasset F et al. The effect of increasing the dose of hydroxychloroquine (HCQ) in patients with refractory cutaneous lupus erythematosus (CLE): An open-label prospective pilot study. J Am Acad Dermatol 2016 Apr; 74:693. (http://dx.doi.org/10.1016/j.jaad.2015.09.064)

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